PCF8562TT Datasheet, PDF (21/44 Pages) NXP Semiconductors – Universal LCD driver for low multiplex rates

NXP Semiconductors
PCF8562
Universal LCD driver for low multiplex rates
• In 1:2 multiplex mode, rows 0 and 1 are selected
• In static mode, row 0 is selected
The PCF8562 includes a RAM bank switching feature in the static and 1:2 multiplex drive
modes. In the static drive mode, the bank-select command may request the content of
row 2 to be selected for display instead of the content of row 0. In the 1:2 multiplex mode,
the content of rows 2 and 3 may be selected instead of rows 0 and 1. This gives the
provision for preparing display information in an alternative bank and to be able to switch
to it once it is assembled.
7.10.5 Input bank selector
The input bank selector loads display data into the display RAM in accordance with the
selected LCD drive configuration.
The bank-select command (see Table 14) can be used to load display data in row 2 in
static drive mode or in rows 2 and 3 in 1:2 mode. The input bank selector functions are
independent of the output bank selector.
7.11 Blinking
The display blinking capabilities of the PCF8562 are very versatile. The whole display can
blink at frequencies selected by the blink-select command (see Table 15). The blink
frequencies are fractions of the clock frequency. The ratio between the clock and blink
frequencies depends on the blink mode selected (see Table 8).
An additional feature is for an arbitrary selection of LCD elements to blink. This applies to
the static and 1:2 multiplex drive modes and can be implemented without any
communication overheads. By means of the output bank selector, the displayed RAM
banks are exchanged with alternate RAM banks at the blink frequency. This mode can
also be specified by the blink-select command.
In the 1:3 and 1:4 multiplex modes, where no alternative RAM bank is available, groups of
LCD elements can blink by selectively changing the display RAM data at fixed time
intervals.
Table 8. Blinking frequencies^[1]
Blink mode
Normal operating mode ratio
off
-
1
-^f--^c---^l-^k--
768
2
---^f--^c--^l--^k---
1536
3
---^f--^c--^l--^k---
3072
Nominal blink frequency
blinking off
2 Hz
1 Hz
0.5 Hz
[1] Blink modes 1, 2, and 3 and the nominal blink frequencies 0.5 Hz, 1 Hz, and 2 Hz correspond to an
oscillator frequency (f_clk) of 1536 Hz (see Section 12).
The entire display can blink at a frequency other than the nominal blink frequency. This
can be effectively performed by resetting and setting the display enable bit E at the
required rate using the mode-set command (see Table 11).
PCF8562
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 6 — 16 June 2011
© NXP B.V. 2011. All rights reserved.
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